In the oilfield industry, two main parameters are used to assess enhanced oil recovery (EOR) techniques in terms of its efficiency: interfacial tension and surface (wettability) alteration. The impact of these parameters on recovering what is left in the reservoir is important. Although, there is currently an interest in brine injection as a potential-EOR method, the role of interfacial tension and wettability alteration is not well understood. In a hydrocarbon reservoir, when brine and oil come in contact, they create a particular angle with the rock surface. If the brine concentration changes, such as being reduced by pumping fresh water or seawater into the reservoir, the corresponding contact angle changes.
Conventional techniques of contact angle measurements on reservoir rocks at downhole conditions are very complicated. They are highly sensitive and require good core preservation and preparation. Accordingly, there is a need for better understanding of the role of interfacial tensions and wettability, as well as improved methods for determining wettability alteration due to changes in fluid composition.